CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
2.
θ
JA
is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
Test Conditions: V
CC
= 3V to 5.5V, C
1
- C
4
= 0.1µF; Unless Otherwise Specified.
Typicals are at T
A
= 25°C
TEST CONDITIONS
TEMP
(°C)
MIN
TYP
MAX
UNITS
PARAMETER
DC CHARACTERISTICS
Supply Current, Powerdown
SHDN = GND
25
Full
-
-
-
0.1
1
0.3
5
50
3.0
µA
µA
mA
Supply Current, Enabled
All Outputs Unloaded, SHDN = V
CC
Full
LOGIC AND TRANSMITTER INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low
Input Logic Threshold High
Input Leakage Current
Output Leakage Current
Output Voltage Low
Output Voltage High
RECEIVER INPUTS
Input Voltage Range
Input Threshold Low
V
CC
= 3.3V
V
CC
= 5.0V
Input Threshold High
V
CC
= 3.3V
V
CC
= 5.0V
Input Hysteresis
Input Resistance
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
Output Short-Circuit Current
Output Leakage Current
TIMING CHARACTERISTICS
Maximum Data Rate
R
L
= 3kΩ, C
L
= 1000pF, One Transmitter Switching
Full
250
500
-
Kbps
V
OUT
=
±12V,
V
CC
= 0V or 3V to 5.5V, SHDN = GND
All Transmitter Outputs Loaded with 3kΩ to Ground
V
CC
= V+ = V- = 0V, Transmitter Output =
±2V
Full
Full
Full
Full
±5.0
300
±7
-
±5.4
10M
±35
-
-
-
-
±10
V
Ω
mA
µA
Full
25
Full
25
Full
Full
Full
-25
0.6
0.8
-
-
0.2
3
-
1.2
1.5
1.5
1.8
0.5
5
25
-
-
2.4
2.4
1
7
V
V
V
V
V
V
kΩ
T
IN
, SHDN
T
IN
, SHDN
T
IN
, SHDN
SHDN = GND
I
OUT
= 3.2mA
I
OUT
= -1.0mA
Full
Full
Full
Full
Full
Full
-
2.4
-
-
-
-
-
±0.01
±0.05
-
0.8
-
±1.0
±10
0.4
-
V
V
µA
µA
V
V
V
CC
-0.6 V
CC
-0.1
3
FN6017.3
March 15, 2005
ISL83384E
Electrical Specifications
Test Conditions: V
CC
= 3V to 5.5V, C
1
- C
4
= 0.1µF; Unless Otherwise Specified.
Typicals are at T
A
= 25°C
(Continued)
TEST CONDITIONS
Transmitter Input to
Transmitter Output,
C
L
= 1000pF
Receiver Input to Receiver
Output, C
L
= 150pF
t
PHL
t
PLH
t
PHL
t
PLH
TEMP
(°C)
Full
Full
Full
Full
25
25
25
25
25
25
MIN
-
-
-
-
-
-
-
-
4
6
TYP
0.6
0.7
0.2
0.3
50
600
100
100
-
-
MAX
3.5
3.5
1
1
-
-
-
-
-
-
UNITS
µs
µs
µs
µs
µs
ns
ns
ns
V/µs
V/µs
PARAMETER
Transmitter Propagation Delay
Receiver Propagation Delay
Transmitter Output Enable Time
Transmitter Output Disable Time
Transmitter Skew
Receiver Skew
Transition Region Slew Rate
From SHDN Rising Edge to T
OUT
=
±3V
From SHDN Falling Edge to T
OUT
=
±5V
t
PHL
- t
PLH
(Note 3)
t
PHL
- t
PLH
V
CC
= 3.3V, C
L
= 150pF to
R
L
= 3kΩ to 7kΩ,
Measured From 3V to -3V or 2500pF
-3V to 3V
V
CC
= 4.5V, C
L
= 150pF to
2500pF
ESD PERFORMANCE
RS-232 Pins (T
OUT
, R
IN
)
Human Body Model
IEC61000-4-2 Contact Discharge
IEC61000-4-2 Air Gap Discharge
All Other Pins
NOTE:
3. Transmitter skew is measured at the transmitter zero crossing points.
Human Body Model
25
25
25
25
-
-
-
-
±15
±8
±15
±3
-
-
-
-
kV
kV
kV
kV
Detailed Description
The ISL83384E operates from a single +3V to +5.5V supply,
guarantees a 250Kbps minimum data rate, requires only four
small external 0.1µF capacitors, features low power
consumption, and meets all ElA RS-232C and V.28
specifications. The circuit is divided into three sections: The
charge pump, the transmitters, and the receivers.
All transmitter outputs disable and assume a high
impedance state when the device enters the powerdown
mode (see Table 2). These outputs may be driven to
±12V
when disabled.
All devices guarantee a 250Kbps data rate for full load
conditions (3kΩ and 1000pF), V
CC
≥
3.0V, with one
transmitter operating at full speed. Under more typical
conditions of V
CC
≥
3.3V, R
L
= 3kΩ, and C
L
= 250pF, one
transmitter easily operates at 900Kbps.
Transmitter inputs float if left unconnected (there are no pull-
up resistors), and may cause I
CC
increases. Connect
unused inputs to GND for the best performance.
TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE
SHDN TRANSMITTER RECEIVER
INPUT
OUTPUTS
OUTPUTS MODE OF OPERATION
H
L
Active
High-Z
Active
High-Z
Normal Operation
Manual Powerdown
Charge-Pump
Intersil’s new ISL83384E utilizes regulated on-chip dual
charge pumps as voltage doublers, and voltage inverters to
generate
±5.5V
transmitter supplies from a V
CC
supply as
low as 3.0V. This allows these devices to maintain RS-232
compliant output levels over the
±10%
tolerance range of
3.3V powered systems. The efficient on-chip power supplies
require only four small, external 0.1µF capacitors for the
voltage doubler and inverter functions over the full V
CC
range. The charge pumps operate discontinuously (i.e., they
turn off as soon as the V+ and V- supplies are pumped up to
the nominal values), resulting in significant power savings.
Transmitters
The transmitters are proprietary, low dropout, inverting
drivers that translate TTL/CMOS inputs to EIA/TIA-232
output levels. Coupled with the on-chip
±5.5V
supplies, these
transmitters deliver true RS-232 levels over a wide range of
single supply system voltages.
Receivers
The ISL83384E contains standard inverting receivers that
three-state via the SHDN control line. Receivers driving
powered down peripherals must be disabled to prevent
current flow through the peripheral’s protection diodes (see
Figures 2 and 3).
4
FN6017.3
March 15, 2005
ISL83384E
All the receivers convert RS-232 signals to CMOS output
levels and accept inputs up to
±30V
while presenting the
required 3kΩ to 7kΩ input impedance (see Figure 1) even if
the power is off (V
CC
= 0V). The receivers’ Schmitt trigger
input stage uses hysteresis to increase noise immunity and
decrease errors due to slow input signal transitions.
V
CC
R
XIN
-25V
≤
V
RIN
≤
+25V
GND
5kΩ
R
XOUT
GND
≤
V
ROUT
≤
V
CC
GND
V
CC
V
CC
CURRENT
FLOW
V
OUT
= V
CC
Rx
POWERED
DOWN
UART
Tx
SHDN = GND
OLD
RS-232 CHIP
V
CC
FIGURE 1. INVERTING RECEIVER CONNECTIONS
Low Power Operation
This 3V device requires a nominal supply current of 0.3mA,
even at V
CC
= 5.5V, during normal operation (not in
powerdown mode). This is considerably less than the 11mA
current required by comparable 5V RS-232 devices, allowing
users to reduce system power simply by replacing the old
style device with the ISL83384E.
FIGURE 2. POWER DRAIN THROUGH POWERED DOWN
PERIPHERAL
V
CC
Low Power, Pin Compatible Replacement
Pin compatibility with existing 5V products (e.g., MAX222),
coupled with the wide operating supply range, make the
ISL83384E a potential lower power, higher performance
drop-in replacement for existing 5V applications. As long as
the
±5V
RS-232 output swings are acceptable, and
transmitter pull-up resistors aren’t required, the ISL83384E
should work in most 5V applications.
When replacing a device in an existing 5V application, it is
acceptable to terminate C
3
to V
CC
as shown on the “Typical
Operating Circuit”. Nevertheless, terminate C
3
to GND if
possible, as slightly better performance results from this
configuration.
TRANSITION
DETECTOR
TO
WAKE-UP
LOGIC
V
CC
V-
ISL83384E
R
X
POWERED
DOWN
UART
V
OUT
= HI-Z
T
X
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
Powerdown Functionality
The already low current requirement drops significantly
when the device enters powerdown mode. In powerdown,
supply current drops to 1µA, because the on-chip charge
pump turns off (V+ collapses to V
CC
, V- collapses to GND),
and the transmitter and receiver outputs three-state. This
micro-power mode makes these devices ideal for battery
powered and portable applications.
SHDN
PWR
MGT
LOGIC
ISL83384E
Software Controlled (Manual) Powerdown
The ISL83384E may be forced into its low power, standby
state via a simple shutdown (SHDN) pin (see Figure 4).
Driving this pin high enables normal operation, while driving
it low forces the IC into its powerdown state. The time
required to exit powerdown, and resume transmission is less
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